According to Pindar, a goddess attempted to imitate the sound of two of these beings crying by inventing the aulos flute. (-5[1])Two drops of blood from these beings (10[1])were gifted to either Erichthonius or Asclepius for use as a panacea. The death of one of these beings spilled blood (-5[1])that mixed with sand (10[1])to create the viper that killed the Argonaut Mopsus and created a warrior named for being born with a golden sword. (10[1])Ceto (10[1])mothered two immortal examples (-5[1])of these beings named Stheno and Euryale. The head of the only mortal one of (10[1])these sisters is placed on the aegis by Athena after (10[1])Chrysaor and Pegasus are born from her beheading (-5[1])by Perseus. For 10 points, what snake-haired sisters from Greek myth include (10[1])Medusa? ■END■ (10[2])